Use measured values when possible
Pipe volume depends on the actual inside diameter, which can differ from nominal pipe size. Flow rate also changes with pressure, valves, aerators, restrictions and fixture condition.
FREE PLUMBING TOOLS
Practical Plumbing Calculators
Estimate pipe water volume and measure faucet or fixture flow rate with quick browser-based calculators.
No sign-up required
Calculations run in your browser. Results are planning estimates and are not a substitute for local code requirements or professional diagnosis.
PIPE MEASUREMENT
Pipe Volume Calculator
Enter inside diameter and pipe length to estimate how much water the pipe can hold in gallons and liters.
Open calculator →WATER FLOW
Flow Rate Calculator
Measure a known volume of water and the fill time to calculate gallons per minute and liters per minute.
Open calculator →Know when to call a professional
These calculators help with simple measurements. Gas lines, sewage, major leaks, code work, concealed piping and unsafe electrical conditions should be handled by qualified professionals.